Gel catalysts and methods for their use in catalytic dehydrogenation processes

ABSTRACT

A gel composition substantially contained within the pores of a solid material is disclosed for use as a catalyst or as a catalyst support in dehydrogenation and dehydrocyclization processes.

FIELD OF THE INVENTION

[0001] The present invention relates to a novel composition comprising agel that has utility as a catalyst or as a catalyst support. Alsodisclosed are methods of preparing the compositions and processes forusing the compositions for the dehydrogenation of C₂₋₁₀ hydrocarbons.

BACKGROUND OF THE INVENTION

[0002] The dehydrogenation of paraffins to olefins is commerciallysignificant because of the need for olefins for the manufacture of highoctane gasolines, elastomers, detergents, plastics, ion-exchange resinsand pharmaceuticals. Important hydrocarbon dehydrocyclization reactionsinclude the conversion of diisobutylene and isooctane to p-xylene.

[0003] Processes for the conversion of paraffin hydrocarbons to lesssaturated hydrocarbons are known. For examples, see U.S. Pat. No.4,513,162, U.S. Pat. No. 5,378,350 and European Pat. Application EP947,247 (published). Nonetheless, there is a continuing need to developnew compositions that are more effective catalysts than those currentlyavailable in dehydrogenation processes.

SUMMARY OF THE INVENTION

[0004] The present invention discloses a composition of matter,comprising: (i) a solid material having pores; (ii) a gel, said gelbeing substantially contained within the pores of said solid materialand comprising at least one catalytically active element, and optionallywhen said catalytically active element is other than Cr, comprisingchromium in addition to said element.

[0005] Another disclosure of the present invention is a process forpreparing a composition of matter comprising: a solid material havingpores; a gel, said gel being substantially contained within the pores ofsaid solid material and comprising at least one catalytically activeelement, and optionally when said catalytically active element is otherthan Cr, comprising Cr in addition to said element, said processcomprising: contacting in the presence of a solid material having pores,in any order a protic solution with a non-aqueous solution wherein saidnon-aqueous solution comprises a gel-forming precursor and wherein oneof either the protic solution or the non-aqueous solution comprises atleast one soluble compound comprising an inorganic element selected fromthe group consisting of Group 1 through Group 16 and the lanthanides ofthe Periodic Table, under conditions such that the solution added firstis at incipient wetness, whereby gel formation occurs substantiallywithin the pores of said solid material.

[0006] A further disclosure of the present invention is a composition ofmatter prepared by the process described immediately above.

[0007] The present invention also discloses an improved gel composition,wherein said improvement comprises: said gel is substantially containedwithin the pores of a solid material.

[0008] Yet another disclosure of the present invention is a method ofusing the composition disclosed wherein said method comprises contactingin a reactor said composition with a hydrocarbon feed in adehydrogenation or dehydrocyclization process, said hydrocarbon beingfrom C₂ to C₁₀.

DETAILED DESCRIPTION OF THE INVENTION

[0009] The solid material having pores is selected from the groupconsisting of alumina, silica, titania, zirconia, carbon, molecularsieves (for example, zeolites), porous minerals (such as bentonite),microporous, mesoporous and macroporous materials, montmorillonites,aluminosilicate clays (for example, bentonite), binary ternary,quaternary and higher order oxides such as e.g., Fe₂O₃, NiO, CaO andCeO₂ (binary oxides), FeNbO₄, NiWO₄ and Sr₂TiO₄ (ternary oxides) andCa₂MgSi₂O₇ (quaternary oxide), carbides, nitrides, phosphates, andsulfides. These materials are used as supports for the gels.

[0010] Higher order oxides are oxides beyond quaternary that containmore than four elements, including oxygen. Some examples of higher orderoxides include ganomalite (Pb₉Ca₅MnSi₉O₃₃), a lead calcium magnesiumsilicate, sodium calcium nickel arsenate (NaCa₂Ni₂As₃O₁₂) and bariumcopper europium lanthanum thorium oxide(Ba_(1.33)La_(0.67)Eu_(1.5)Th_(0.5)Cu₃O_(8.89)).

[0011] Catalytically active elements, which can be present as oxides,reduced metals, and in some cases phosphates of Group 1 (Li, Na, K, Rb,Cs), Group 2 (Be, Mg, Ca, Sr and Ba), Group 3 (Y, La) and thelanthanides (Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm Yb and Lu) ofthe Periodic Table can be used in C—H activation catalytic chemistries.Examples include methane coupling reactions to produce ethane andethylene. In combination with other oxides of Groups 5, 6, 7, 8, 9, 10of the Periodic Table, Groups 1, 2, 3 and the lanthanides can also beused for other oxidation chemistries. Alkane and olefin oxidation aretwo examples. Group 5 (V, Nb, Ta), Group 6 (Cr, Mo, W), Group 7 (Mn, andRe), and Group 9 (Fe, Ru, Os), can be used for oxidation reactions ofalkanes and olefins. Two examples are the oxidation of butane to maleicanhydride and propylene oxidation to form acrolein. Elements of Group 10(Ni, Pd, Pt) and Group (11, Cu, Ag, and Au) can be used for alkane andolefin oxidation reactions, CO abatement, and for Pd, Pt, hydrogenationchemistries such as hydrogenation of ethylene to ethane. Ag and itsoxides can be used in epoxidation reactions, such as the epoxidation ofethylene to produce ethylene oxide. Elements of Group 15, especially P,As, Sb Bi can be used for oxidation reaction chemistries, such as theammoxidation of propylene to acrylonitrile, especially when combinedwith elements of Group 6 (Cr, Mo, and W) to form various oxidecombinations. Elements and their oxides of Group 16 (S, Se and Te) canbe used for dehydrosulfirization chemistries, which are used to treatsulfur containing streams from petroleum distillates.

[0012] The gel is prepared from at least one soluble compound comprisingan inorganic element precursor wherein at least one element is selectedfrom the group consisting of Group 1 (i.e., Li, Na, K, Rb and Cs); Group2 (i.e., Be, Mg, Ca, Sr and Ba); Group 3 (i.e., Y and La); Group 4(i.e., Ti, Zr and Hf); Group 5 (i.e., V, Nb and Ta); Group 6 (i.e., Cr,Mo and W); Group 7, (i.e., Mn and Re); Group 8 (i.e., Fe, Ru and Os);Group 9 (i.e., Co, Rh and Ir); Group 10 (Ni, Pd and Pt); Group 11 (Cu,Ag and Au); Group 12 (i.e., Zn and Cd); Group 13 (i.e., B, Al and In);Group 14 (i.e.; Si, Ge, Sn and Pb); Group 15 (i.e.; P, As, Sb and Bi);Group 16 (i.e., S, Se and Te) and lanthanides (i.e.; Ce, Pr, Nd, Sm, Eu,Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) of the Periodic Table.

[0013] In the present invention one or more inorganic alkoxides or saltsthereof is used as starting material, or precursors, for preparing thegels. The gel-forming precursor comprises at least one soluble compoundcomprising an inorganic element wherein the element is selected from thegroup consisting of aluminum, silicon, titanium zirconium, niobium,tantalum, vanadium, molybdenum and chromium. The alkoxides are thepreferred compounds, and metal alkoxides are most preferred.

[0014] The inorganic metal alkoxides used in this invention may includeany alkoxide which contains from 1 to 20 carbon atoms and preferably 1to 5 carbon atoms in the alkoxide group, which preferably are soluble inthe liquid reaction medium. Examples include, but are not limited to,tantalum n-butoxide, titanium isopropoxide, aluminum isopropoxide andzirconium isopropoxide. These alkoxides are preferred.

[0015] Inorganic materials have a range of pore sizes. Pore dimensionsfor some inorganic materials are relatively small. The present inventiondiscloses gel-forming precursors that fit within the pore structure ofthe solid materials that are used. Commercially available alkoxides canbe used. However, inorganic alkoxides can be prepared by other routes.

[0016] Inorganic alkoxides can be prepared in various ways. One methodof preparation includes direct reaction of zero valent metals withalcohols in the presence of a catalyst. Many alkoxides can be formed byreaction of metal halides with alcohols. Also, alkoxy derivatives can besynthesized by the reaction of the alkoxide with alcohol in a ligandinterchange reaction. Direct reactions of metal dialkylamides withalcohol also form alkoxide derivatives. Additional methods for preparingalkoxides are disclosed in “Metal Alkoxides” by D. C. Bradley et al.,Academic Press, (1978).

[0017] The gel formed in the composition of the present invention ismade by preparing one or more non-aqueous alkoxide (or salt) solutionsand a separate solution of a protic solvent, such as water. Promotersand other reagents may be added to the solution(s) of alkoxides. Whenthe alkoxide solution is mixed with the protic solvent the alkoxidehydrolyzes and cross-links to form a gel.

[0018] The solvent media used in the process generally should be asolvent for the inorganic alkoxide or alkoxides which are utilized andthe additional metal reagents and promoters which are added insynthesis. Solubility of all components in their respective media(aqueous and non-aqueous) is preferred to produce highly dispersedmaterials. By using soluble reagents in this manner, mixing anddispersion of the active metals and promoter reagents can be nearatomic, in fact mirroring their dispersion in their respectivesolutions. The precursor gel thus produced by this process will containhighly dispersed active metals and promoters. High dispersion results incatalyst metal particles in the nanometer size range. These particlesare substantially contained, or substantially localized, within thepores of the solid material.

[0019] Typically, the concentration of the amount of solvent used islinked to the alkoxide content. A molar ratio of 26.5:1 ethanol:totalalkoxide can be used, although the molar ratio of ethanol:total alkoxidecan be from about 5:1 to 53:1, or even greater. If a large excess ofalcohol is used, gelation will not generally occur immediately; somesolvent evaporation will be needed. At lower solvent concentrations, itis thought that a heavier gel will be formed having less pore volume andsurface area.

[0020] In the process of the present invention, the alkoxide solutionwith other reagents, water and additional aqueous solutions arecontacted in the presence of a solid having pores. Due to the surfacearea provided by the porous character of the solid material, hydrolysisand condensation occurs substantially within the pores of the solid toform the gel.

[0021] The amount of water utilized in the reaction is the amountcalculated to hydrolyze the inorganic alkoxide in the mixture. A ratiolower than that needed to hydrolyze the alkoxide species will result ina partially hydrolyzed material which, in most cases, would reach a gelpoint at a much slower rate, depending on the aging procedure and thepresence of atmospheric moisture. Generally, a molar ratio ofwater:alkoxide from about of 0.1:1 to 10:1 is used.

[0022] Reaction conditions and choice of gel-forming precursor (i.e., aprecursor which can react, hydrolyze and cross-link to form the gel)favors rapid hydrolyses and condensation reactions inside the pores ofthe solid material. These hydrolyses and condensation reactions need tobe more rapid than any reactions that occur outside the pores of thesolid material.

[0023] The molar ratio of the total water added to total catalyticallyactive element added (for example, Ti, Zr, Ta, and Al), including waterpresent in aqueous solutions, varies according to the specific inorganicalkoxide used. For tantalum(alkoxide)₅ ratios close to 5:1 can be used.Also, a ratio of 4:1 can be used for zirconium(alkoxide)₄ andtitanium(alkoxides)₄. The addition of acidic or basic reagents to theinorganic alkoxide medium can have an effect on the kinetics of thehydrolysis and condensation reactions, and the microstructure of theoxyhydroxide matrices derived from the alkoxide precursor that comprisesthe soluble inorganic element. Generally, a pH within the range of from1 to 12 can be used, with a pH range of from 1 to 6 being preferred.

[0024] The first addition step is done under conditions of incipientwetness. The order of addition is not important, i.e., the either theprotic solvent or the non-aqueous solvent can be added initially. Thesecond addition step can optionally be done under incipient wetnessconditions.

[0025] After gel formation occurs within the pores of the solidmaterial, it may be necessary to complete the gelation process with someaging of the gel composition. This aging can range form one minute toseveral days. In general, the gel is aged in the pores of the solidmaterial at room temperature in air for at least several hours.

[0026] Removal of solvent from the gel composition can be accomplishedby several methods. Removal by vacuum drying or heating in air resultsin the formation of a xerogel. A gel that is an aerogel of the materialtypically can be formed by charging in a pressurized system such as anautoclave. The gel composition can be placed in an autoclave where itcan be contacted with a fluid above its critical temperature andpressure by allowing supercritical fluid to flow through the gelmaterial until the solvent is no longer being extracted by thesupercritical fluid. In performing this extraction to produce an aerogelmaterial, various fluids can be utilized at their critical temperatureand pressure. For example, fluorochlorocarbons typified by Freon®fluorochloromethanes (e.g., Freon® 11 (CCl₃F), 12 (CCl₂F₂) or 114(CClF₂CClF₂), ammonia and carbon dioxide are all suitable for thisprocess. Typically, the extraction fluids are gases at atmosphericconditions. The pores collapse due to the capillary forces at theliquid/solid interface are avoided during drying.

[0027] The gels formed within the pores of the solid material, whetherthey are xerogels or aerogels, can be described as precursor saltsdispersed in an oxide or oxyhydroxide matrix. The theoretical maximumfor hydroxyl content corresponds to the valence of central metal atom.Hence, Ta₂(O_(2-x)(OH)_(x))₅ possesses a theoretical hydroxyl maximumwhen x is 2. The molar H₂O:alkoxide ratio can also impact the finalxerogel stoichiometry; in this case, if H₂O:Ta is less than 5, therewill be residual —OR groups in the unaged gel. However, reaction withatmospheric moisture will convert these to the corresponding —OH, and —Ogroups upon continued polymerization and dehydration. Aging, even underinert conditions, can also effect the condensation of the —OH,eliminating H₂O, through continuation of crosslinking andpolymerization, i.e., gel formation.

[0028] The gel compositions of the present invention have utility ascatalysts or as improved catalyst supports. The solid material havingpores provides mechanical integrity for the gel and generally does notinhibit the catalytic properties of the gel. The mechanical integritypermits easier handling and transportation of the gel compositionssince, without the solid material, these compositions are fluffy andpowder-like, and not easily contained. In turn, the gel compositionsdisclosed herein reduce waste and therefore, is more cost efficient.

[0029] One particular use of the compositions of the present inventionis in the dehydrogenation of C₂ to C₁₀ hydrocarbons. In thedehydrogenation process disclosed herein, the hydrocarbon feed that canbe used in the present invention includes any C₂ to C₁₀ hydrocarbon withethane, propane, isobutane and isooctane (2,2,4-trimethylpentane) beingpreferred. The gel compositions contained within the pores of the solidmaterials disclosed in the present invention can be used as catalysts bycontacting the gel composition with the hydrocarbon feed in adehydrogenation process in a reactor. The contacting step may be done invarious types of reactors, including a fixed bed, moving bed, fluidizedbed, ebullating bed and entrained bed. The less saturated hydrocarbonreaction products of this invention can be separated by conventionalmeans such as distillation, membrane separation and absorption.

[0030] The gas hourly space velocity (GHSV) of the feed gas generally isin the range of from about 100 to about 3000 cc hydrocarbon feed/cc gelcomposition/hour, preferably from about 500 to about 1000 cc hydrocarbonfeed/cc gel composition/hour. The operating pressure is generally in therange of from about 7 kPa to about 700 kPa, preferably from about 7 kPato about 400 kPa. The dehydrogenation reaction temperature generally isin the range of from about 300° C. to about 650° C., preferably fromabout 450° C. to 600° C.

[0031] The gel-containing compositions of this invention can beregenerated periodically to remove coke. The regeneration is done byconventional techniques of carbon removal such as heating with anoxygen-containing gas, preferably air.

[0032] The compositions of the present invention are also useful ascatalyst supports. For example, a chromium/aluminum gel supported ineta-alumina, prepared as described in Example 1 below, can beimpregnated with a water soluble compound of platinum. One such examplewould be impregnation with H₂PtCl₄. The impregnated support is thendried and heated to 400° C. in a 5% hydrogen/nitrogen stream for 4 hoursand then cooled. The reduced supported catalyst is then suspended in asolvent containing 1-hexene. The suspension is then heated at about 100°C. with stirring under a hydrogen atmosphere at about 3000 kPa for abouttwo hours. Hexane can be separated from the reaction mixture.

[0033] In addition to the utility disclosed above, the compositions ofthe present invention also can be used as catalyst supports foroxidation (e.g., supported cobalt) and hydroformylation (e.g. supportedrhodium) reactions.

[0034] The process for making the present invention may be implementedby using combinatorial methods for the rapid syntheses of catalysts.Such methods would permit the production of these catalysts usingrobotic tools, such as liquid delivery system, to a solid having pores,as described in the present invention, to create gel compositionssubstantially in the pores of the solid.

EXAMPLES

[0035] The catalyst charge was 2 mL for all the examples.

General Procedure for Catalyst Testing

[0036] Catalyst tests were performed in a fixed bed continuous flowquartz reactor with 6.4 mm id. The catalyst charge was 2.0 mL of −12/+20mesh (−1.68/+0.84 mm) granules. The reactor tube was heated in a tubefurnace to 550° C. in flowing nitrogen until the temperature was stable.A thermocouple inside the catalyst bed was used to measure temperature.Once the desired temperature was achieved, a feed consisting of 50%isobutane/50% nitrogen (Examples 1 to 4) or a feed consisting of 50%propane/50% nitrogen (Examples 5 to 6) were passed over the catalystbed. The contact times 3.2 seconds in all the examples. The entireproduct stream was analyzed on-line using sampling valves and an HP 5890chromatogram (TCD)/HP 5971 mass selective detector.

[0037] The gel compositions prepared in the Examples below were used indehydrogenation processes. The results are tabulated and are shown belowin Table 1 (isobutane dehydrogenation) and Table 2 (propanedehydrogenation). Legend C₃ is CH₃CH₂CH₃ C₃ = is CH₂═CHCH₃ iC4 is(CH₃)₂CHCH₃ iC4 = is (CH₃)₂C═CH₂

EXAMPLE 1 (Cr_(0.2)Al_(0.8))_(0.0383)(eta-Al₂O₃)_(0.96169)

[0038] A sol gel of chromium hydroxide acetate/aluminum isopropoxidecontained in the pores of eta alumina was prepared as follows: etaalumina (8.0 g, N₂ BET surface area=401.9 m²/g, pore volume=0.327474cc/g) was used. An aqueous solution containing 0.1 M (with respect tochromium) (Cr₃(OH)₂)(ac)₇ was prepared by dissolving the chromium salt(4.022 g) in a sufficient quantity of commercially available ammoniumhydroxide solution (28-30% NH₄OH in water) to bring the solution volumeto 200 mL. In a first sol gel preparation, the chromium solution (5 mL)was first added dropwise to the eta alumina support with agitation.Following addition of the aqueous solution, 0.05 M aluminum isopropoxidein isopropanol (20 mL) was slowly added to the wet support. Excesssolvent was used in this preparation (however, the aluminum isopropoxidewill deposit inside of the pores of the supports to graft onto it). Thesolid was allowed to dry in air prior to the second impregnation.

[0039] In a second cycle, additional chromium solution (2.5 mL) wasadded, and additional aluminum isopropoxide solution (20 mL) was addedinto the support. In a third cycle, 2.7 mL of the chromium solution wasused, and 20 mL of the aluminum isopropoxide solution was employed. In afourth cycle, 2.2 mL of the chromium solution was added along with 0.3mL of NH₄OH solution was added, followed by 20 mL of the aluminumisopropoxide solution. The final cycle involved the addition of 2.5 mLof ammonium hydroxide solution (only) followed by 20 mL of the aluminumisopropoxide. The final material was dried under vacuum for 5 hours at120° C. The material was pelletized and granulated and sieved on −10,+20 mesh (−2.0, +0.84 mm) screens prior to reactor evaluations. Highresolution transmission electron microscopy depicted Example 1 andshowed that the chromium-alumina gel is essentially within the pores ofthe eta-alumina solid material (support).

EXAMPLE 2 Cr_(0.0182)Al_(0.0285)(TiO₂)_(0.9533)

[0040] A portion (7.7 mL) of the 0.1 M (with respect tochromium)solution of chromium hydroxide acetate described in Example 1was added to titanium oxide (8 g), followed by 20 mL of the 0.05 Maluminum isopropoxide solution (described in Example 1) to add thealkoxide into the support. In a second cycle, 6.7 mL and 20 mL of thechromium and aluminum solutions, respectively, were used. In a thirdcycle, 4.75 mL and 20 mL of the chromium and aluminum solutions,respectively, were used. The final material was dried under vacuum for 5hours at 120° C. The material was pelletized and granulated and sievedon −10, +20 mesh (−2.0, +0.84 mm) screens prior to reactor evaluations.

EXAMPLE 3 5.261 wt % (CrO_(1.5)), 1.193 wt % (AlO_(1.5)), 93.546 wt %Bentonite Clay

[0041] Bentonite clay (8 g) was used as a support. A 2.5 mL portion ofthe 0.1 M (with respect to chromium) chromium hydroxide acetate solutionfrom Example 1 was used, followed by 20 mL of the aluminum isopropoxidesolution from Example 1. One additional cycle was used to bring thecatalyst to the final loading. The fmal material was dried under vacuumfor 5 hours at 120° C. The material was pelletized and granulated andsieved on −10, +20 mesh (−2.0, +0.84 mm) screens prior to reactorevaluations.

EXAMPLE 4 Cr_(0.003432)Al_(0.0137266)/C_(0.9828414)

[0042] A 5 mL portion of the 0.1 M (with respect to chromium) chromiumhydroxide acetate solution from Example 1 was added to carbon black(6.88 g) followed by 40 mL of the aluminum isopropoxide solution. In asecond cycle, 5 mL of the chromium solution and 40 mL of the aluminumhydroxide solution were used. A third cycle used 5 and 40 mL, and afourth cycle 4 and 40 mL were used. The final material was dried undervacuum for 5 hours at 120° C. The material was pelletized and granulatedand sieved on −10, +20 mesh (−2.0, +0.84 mm) screens prior to reactorevaluations.

EXAMPLE 5 Cr_(0.0182)Al_(0.0285)(TiO₂)_(0.9533)

[0043] This example was prepared as described in Example 2.

EXAMPLE 6 5.261 wt % (CrO_(1.5)), 1.193 wt % (AlO_(1.5)), 93.546 wt %Bentonite Clay

[0044] This example was prepared as described in Example 3.

EXAMPLE 7 Cr_(0.003432)Al_(0.0137266)/C_(0.9828414)

[0045] 10 grams of a sample from Example 4 was suspended in 10 mL ofwater containing 1 gm of K₂PtCl₄. The sample was heated to 400° C. in a5% hydrogen/nitrogen stream for 4 hours and cooled. The reduced catalyst(0.100 g) was suspended in 1 mL of hexane containing 0.200 gm of1-hexene and heated to 100° C. with 500 psig H₂ for 2 hours. GC analysisof the product showed greater than 95% selectivity for hexane. TABLE 1ISOBUTANE DEHYDROGENATION Ex. % iC₄ % iC₄ = % CH₄ % C₂-C₄ % Others No.Conv. Sel. Sel. Sel. Sel. 1 37.2 27.4 31.4 38.4 2.3 2 32.1 60.9 24.414.8 0 3  6.9 64.4 0 35.6 0 4 12.4 83.4 0 16.6 0

[0046] TABLE 2 PROPANE DEHYDROGENATION Ex. % C₃ % C₃ = % C₂ % Others No.Conv. Sel. Sel. Sel. 5 23.0 86.4 8.2 5.5 6 3.2 55.8 40.0 4.2

What is claimed is:
 1. A composition of matter, comprising: (i) a solidmaterial having pores; and (ii) a gel, said gel being substantiallycontained within the pores of said solid material and comprising atleast one catalytically active element, and optionally when saidcatalytically active element is other than chromium, comprising chromiumin addition to said element.
 2. The composition of claim 1 wherein thesolid material having pores is selected from the group consisting ofalumina, silica, titania, zirconia, carbon, molecular sieves, porousminerals, microporous, mesoporous and macroporous materials,montmorillonites, aluminosilicate clays, and binary, ternary, quaternaryand higher order oxides, carbides, nitrides, phosphates, and sulfides.3. The composition of claim 1 wherein said catalytically active elementis chromium and said solid material having pores is alumina.
 4. Thecomposition of claim 2 wherein said catalytically active metal isselected from the group consisting of platinum and gold.
 5. A processfor preparing a composition of matter comprising a solid material havingpores; a gel, said gel substantially contained within the pores of saidsolid material and comprising at least one catalytically active element,and optionally when said catalytically active element is other thanchromium, comprising chromium in addition to said element, said processcomprising: contacting in the presence of a solid material having pores,in any order a protic solution with a non-aqueous solution wherein saidnon-aqueous solution comprises a gel-forming precursor and wherein oneof either the protic solution or the non-aqueous solution comprises atleast one soluble compound comprising an inorganic element selected fromthe group consisting of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Y, La,Ti, Zr Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh Ir, Ni, PdPt, Cu, Ag, Au, Zn, Cd, B, Al, In, Si, Ge, Sn, Pb, P, As, Sb, Bi, S, SeTe, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu andlanthanides of the Periodic Table, under such conditions such that thesolution added first is at incipient wetness, whereby gel formationoccurs substantially within the pores of said solid material.
 6. Theprocess of claim 5 wherein the solid material having pores is a catalystsupport selected from the group consisting of alumina, silica, titania,zirconia, carbon, molecular sieve, porous mineral, montmorillonite clay,aluminosilicate clay, carbide, nitride, phosphate, and sulfide and saidgel-forming precursor comprises at least one soluble compound comprisingan inorganic element selected from the group consisting of aluminum,silicon, titanium, zirconium, niobium, tantalum, vanadium, molybdenumand chromium.
 7. The process of claim 6 wherein the catalyst support isalumina and the gel-forming precursor is a chromium salt.
 8. Thecomposition of matter prepared by the process of any one of claims 5, 6or
 7. 9. An improved gel composition, wherein said improvementcomprises: said gel is substantially contained within pores of a solidmaterial selected from the group consisting of alumina, silica, titania,zirconia, carbon, molecular sieves, porous minerals, montmorilloniteclay, aluminosilicate clays, carbides, nitrides, phosphates, andsulfides.
 10. A method of using the composition of claim 1 or theimproved gel composition of claim 9 wherein said method comprisescontacting in a dehydrogenation process reactor said composition with ahydrocarbon feed, said hydrocarbon being from C₂ to C₁₀.
 11. The methodof claim 10 wherein said hydrocarbon is selected from the groupconsisting of ethane, propane, and isobutane.
 12. The method of claim 11wherein the gas hourly space velocity of the feed gas is from about 100cc hydrocarbon feed per cc gel composition per hour to about 3000 cchydrocarbon feed per cc gel composition per hour.
 13. The method ofclaim 12 wherein the gas hourly space velocity of the gas feed is fromabout 500 cc hydrocarbon feed per cc gel composition per hour to about1000 cc hydrocarbon feed per cc gel composition per hour.
 14. The methodof claim 11 wherein said composition is regenerated periodically toremove coke, said regeneration comprising heating said composition withan oxygen-containing gas.